Sanghelios has a gravity of 1.375 Gs, and an average surface temperature of -5C to 56C (23F to 132.8F). Sanghelios is inhabited by approximately 8.132 billion Sangheili. The Bestiarum indicates that Sanghelios is similar to Earth in shape and proportion, though the land masses are more scattered in relation to bodies of water. Like Earth, its atmosphere consists of oxygen, carbon dioxide, and nitrogen, but also has a reddish hue to it, perhaps indicating large amounts of iron or new rock being made by the core.
Being a homeworld, the planet is home to a huge number of civilian Sangheili numbering over eight billion, as well as a large defense force. Sanghelios was possibly an area of heavy conflict between Separist and Loyalist forces.

The name "Sanghelios" comes from the Latin sanguis and the Greekhelios meaning "Blood-Sun". It is implied that this may refer to the emphasis on "blood" in the culture of the warrior Sangheili that live there.